(57) A device for control of a capacitor device for a shunt-connected static compensator
unit (COM1, COM2, COM3) for compensation of reactive power in an electric power network
(NW). The capacitor device comprises a capacitor and a semiconductor valve, connected
in series with said capacitor, with a first semiconductor, corresponding to respectively
a first and a second conduction direction for current through the capacitor. The device
comprises members (VN, FSD, CU) which, in dependence on a voltage (Uab, Ubc, Uca)
sensed at the compensator, alternately generate a firing order for the respective
semiconductor. In addition thereto, the device comprises members which, for each of
the first and second conduction directions, form a deblocking signal, indicating that
the conduction direction associated with the respective firing order does not carry
current, and which thus generate a firing order for the second of the first and second
conduction directions with an optional delay (T1*f*360°) after the occurrence of said
deblocking signal.
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